Here are some things that help me.
Note: I'm not a doctor, nor do I have all the answers, I'm just about to log off for the night and thought this may help at least one person tonight.
1) Log off. All online forums that can, even inadvertently, cause stress are powered down.
2) Make a cup of herbal tea. Hate tea? Sometimes even a few calming sips of cool water help.
3) Diffuser time! I love adding lavender to mine. I set the timer for an hour.
4) Try reading or writing. I have an anxiety practice that I write every night but I also have a bullet journal (so millennial) that accounts what I'm thankful for that day. I also like reading children's bedtime stories. Sounds juvenile but I work at a library so I tell myself it's "research" for future patron interactions. Sometimes, even making a physical list of things I need to accomplish the next day helps get them off my subconscious.
5) Lay down and turn off the lights. Oh crap! Too anxious to lay still? Try stretching. Wiggle your arms and legs, get out that energy!
6) Once you're comfortable, breathe in through your nose to a count of four. Hold to a count of three. Breathe out to a count of four. Repeat five times.
7) Each time a thought pops up in your head. Imagine that thought being put into a cloud (okay, this sounds stupid but it works). Sent the cloud off into the world. Another method is to slowly start counting. Try making it to 30 without being distracted. The minute a distracting thought does enter your mind, start counting over again. Don't give up.
8) Still not working? Try a guided meditation online. Another video I like (I know this is counter-intuitive to my "Logoff" statement but hear me out) s called "Marconi Union- Weightless (official video). I've heard that it was created by an artist specifically creating a way to calm anxiety.
9) If you still can't sleep, try starting the "wind down" ritual again.
10) Still not working, come up with your own ritual. Try not to panic that you're not sleeping. The more you tell yourself that you should be sleeping, the more you're just causing anxiety. Let those expectations go. Let it all go. The cloud thing, remember?
I wish you the best. And if you're not asleep after reading my novel of suggestions, I don't t know what to tell you. Maybe read an old Chemistry text book or something.